The relation between chemical structure of dicarboxylic dihydrazide compounds and nucleation effect in isotactic polypropylene

Abstract

A series of dicarboxylic dihydrazide compounds (DCDH-R-n) were prepared and used as nucleating agents for isotactic polypropylene (iPP). To investigate the relation between chemical structure of nucleating agents and nucleation effect in iPP, the influences of DCDH-R-n on crystallization and melting behaviors of iPP were analyzed by differential scanning calorimeter. The results showed some of dicarboxylic dihydrazide compounds were highly efficient for iPP. The nucleation efficiency of these nucleating agents depended on different substituent groups (R) and the number of methylene groups (n). When R is phenyl or cyclohexyl, the corresponding nucleating agents had relatively excellent nucleation effect. A nucleating agent was likely to have better nucleation effect as the number of methylene groups in the structure increases. In addition, the optimum addition amount of DCDH-R-n in iPP ranged from 0.10 to 0.20 mass% and the crystallization temperatures of nucleated iPP under optimum addition amount reached above 130.0 °C.